ah yes... evidence of fluoride being removed from the body. but that could mean the fluoride from your toothpaste is going straight out, not necessarily that fluoride is being displaced from cell receptors and therefore becoming mobilized and flushed out through the urine via kidneys. see what i'm getting at here?
of course if you knew how much fluoride you are consuming on a daily basis and then did a urine test and fluoride levels were higher than your consumption, then you could safely assume that you are excreting fluoride that has been accumulating in the body. but i don't think i'm a candidate for urine tests because i am not dealing with any doctors/experts at the moment.
even then they would try to abscond from such a request, as it is probably a waste of their precious time, which is better spend prescribing Antibiotics to the population. (lol)